Diamond is extremely valuable to science and technology for its extreme hardness, high thermal conductivity, transparency to a large fraction of the light spectrum, and other exceptional properties. Two decades ago, scientists discovered that diamond can become a superconductor under the right conditions. A superconductor is a material that allows electricity to flow through it with zero resistance.
Until recently the exact process remained unclear. Researchers from Pennsylvania State University, the University of Chicago Pritzker School of Molecular Engineering, and the U.S. Department of Energy National Quantum Information Science Research Center have now provided new insights. They produced extremely high-quality diamond thin films doped with boron atoms. Doping is the process of adding atoms of a different element to change the electrical properties of the host material.
A surprising discovery about superconductivity in diamond
The study revealed that superconductivity in these films is granular. It appears in small separate regions known as superconducting puddles that must connect for electricity to flow without resistance across the entire material. This pattern formed even in films that looked uniform under a microscope. The arrangement of the puddles can be adjusted by changing the magnetic field, electrical current, or temperature.
Scientists identified how electrons move between the puddles. This knowledge allows them to link the puddles more effectively. Better connections could improve performance and allow superconductivity at higher temperatures, making quantum devices more practical and energy efficient. Quantum devices rely on qubits, the basic units of quantum information used in computing and communication.
Diamond also has a natural spin-photon interface. This property means it can connect light and matter without extra components. The material can therefore support both superconducting and semiconductor behaviors on one chip. The results point to future quantum chips that combine quantum computing, quantum communication, and other functions while integrating easily with existing electronics. The research supplies a clear method for engineering diamond superconductors by adjusting boron concentration, crystal orientation, mechanical strain, and other factors.
This research is published in PNAS.
